Skew and internal consistency

The effects of skew on the standardized item alpha were examined with Monte Carlo techniques. Alphas computed from normal variables were compared with alphas from lognormal variables, ranks, and skewed versus normal Likert-type variables. The extent and direction of skew were varied, as was the size of the population interitem correlation (rho), the number of items, and the number of categories for Likert-type variables. Because the average interitem correlation affects alpha and skew affects the average interitem correlation, the effect of skew on the average interitem correlation also was examined. Results indicated that skew decreased the average interitem correlation and produced small decreases in alpha that were largest when skew was large, rho was small, items were skewed in opposite directions, and there were fewer items.     

Probability judgment and subadditivity: The role of working memory capacity and constraining retrieval

In this research, we examined the role that individual differences in working memory (WM) capacity, the strength of alternatives, and time constraints play in probability judgment and subadditivity. With a laboratory-based learning task, Experiment 1 revealed that the degree to which participants’ probability judgments were subadditive was negatively correlated with a measure of WM capacity, even when variance due to short-term memory capacity was removed. In addition, participants were more subadditive when the viable alternatives were all rather weak. Experiment 2 extended the WM-capacity-subadditivity correlation to a population judgment task and revealed that subadditivity increases when the judgment task is performed under time constraints. Results support a model that assumes that people make probability judgments by comparing the focal hypothesis with relevant alternatives retrieved from long-term memory and that people high in WM span include more alternatives in the comparison process. Time constraints are assumed to truncate the alternative generation process, leading to fewer alternatives being recalled from long-term memory.     

Housing pregnant mice (Mus musculus) in small groups facilitates the development of odor-based homing in offspring

Infant mice (Mus musculus) born to dams housed in isolation throughout pregnancy (IsoPreg) begin differentially approaching homenest bedding over clean bedding on Postnatal Day 6. Offspring of dams housed with 2 other potentially pregnant conspecifics (SocPreg) display such homing behavior on Day 4. Earlier onset of homing reflects facilitated olfactory responsiveness in SocPreg pups, rather than qualitative or quantitative differences in IsoPreg versus SocPreg nest odors, body growth, or motoric capabilities. Exposing pregnant IsoPreg dams to SocPreg bedding also accelerated homing onset in the offspring, though not to the same extent as the full social context. Thus, it appears that the facilitation of homing is mediated through the pregnant dam by a combination of chemical cues and other social stimuli.     

Auditory attention to frequency and time: an analogy to visual local-global stimuli

Two priming experiments demonstrated exogenous attentional persistence to the fundamental auditory dimensions of frequency (Experiment 1) and time (Experiment 2). In a divided-attention task, participants responded to an independent dimension, the identification of three-tone sequence patterns, for both prime and probe stimuli. The stimuli were specifically designed to parallel the local-global hierarchical letter stimuli of [Navon D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353-383] and the task was designed to parallel subsequent work in visual attention using Navon stimuli [Robertson, L. C. (1996). Attentional persistence for features of hierarchical patterns. Journal of Experimental Psychology: General, 125, 227-249; Ward, L. M. (1982). Determinants of attention to local and global features of visual forms. Journal of Experimental Psychology: Human Perception and Performance, 8, 562-581]. The results are discussed in terms of previous work in auditory attention and previous approaches to auditory local-global processing.     

Perceiver threat in social interactions with stigmatized others

The extent to which stigmatized interaction partners engender perceivers' threat reactions (i.e., stigma-threat hypothesis) was examined. Experiments 1 and 2 included the manipulation of stigma using facial birthmarks. Experiment 3 included manipulations of race and socioeconomic status. Threat responses were measured physiologically, behaviorally, and subjectively. Perceivers interacting with stigmatized partners exhibited cardiovascular reactivity consistent with threat and poorer performance compared with participants interacting with nonstigmatized partners, who exhibited challenge reactivity. In Experiment 3, intergroup contact moderated physiological reactivity such that participants who reported more contact with Black persons exhibited less physiological threat when interacting with them. These results support the stigma-threat hypothesis and suggest the utility of a biopsychosocial approach to the study of stigma and related constructs.     

Left anterior lobectomy and category-specific naming

Damasio and colleagues (1996) have proposed that the left anterior temporal region supports knowledge pertaining to living objects, whereas more posterior temporal regions play a critical role in naming nonliving things. Accordingly, one might expect that left-sided anterior temporal lobectomy should have a more profound effect on the naming of living as opposed to nonliving things. As part of a multicenter collaborative project, seventy-nine patients (all left-hemisphere speech dominant) were tested pre- and post-left-temporal lobectomy on a task that required naming of living and nonliving items equated for name frequency, familiarity, and visual complexity. Consistent with the proposals of Damasio et al. (1996), left temporal lobectomy impaired naming ability, particularly for living things. When individual outcomes were considered, twice as many patients showed a relative decline in naming living as opposed to nonliving things.